Process of making sodium aluminate.



P. A. EMANUEL.

PROCESS OF MAKING SODIUM ALUMINATE.

APPLIGATION FILED SEPT.29, 1909. 957,848. Patented May 10, 1910.

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PROCESS OF MAKING SODIUM ALUMINATE.

Original application filed May 29, 1909, Serial No. 498,202.

To all whom it may concern:

Be it known that I, PHILIP A. EMANUEL, a citizen of the United States, residing at Aiken, in the county of Aiken and State of South Carolina, have invented certain new and useful Improvements in Processes of Making Sodium Aluminate; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to processes of treat ing ores and is designed to treat ordinary clays in such a manner as to save all their valuable constituents and at the same time make use of the by-products. It is also applicable to the treatment of bauxite and corundum for making aluminates, this application being a division of my former application, Serial No. 199,202, filed May 29,1909.

I carry out my process by an apparatus a part of which is shown in the accompanying drawings, and in which Figure 1 is a side elevation showing my invention. Fig. 2 is a horizontal cross section thereof. Fig. 3 is a cross section through the retort. Fig. i is a side elevation on a larger scale, showing part of the retort and part of the furnace, and Fig. 5 is a partial section showing part of the retort and the manner of securing the wire netting thereon.

Referring to the drawings, A represents the retort, B the furnace portion, and C the portion connecting the retort with the smoke stack.

The retort is composed of a cylindrical body portion 1, having at each end an extended portion 2, forming a ridge on which the portion 8 is bolted. The part 3 is cylindrical, and open at both ends, but having one end bent inwardly to embrace the portion 2, both ends of the retort being exactly similar.

at represents a perforated plate fitting tightly against the end of the retort, a suitable packing 5 of asbestos or similar material being used if desired. Bolts 6 pass through the bent-in end of the part 3 through the part 2 and through the plate uniting the whole firmly together.

'7 represents tubes which pass through the end plates 4:, the ends of which are secured in perforations in the plate 8, secured to the plate a.

At the top and bottom the retort is pro- Specification of Letters Patent.

Patented May 10, 1910.

Divided and this application filed September 29,

Serial No. 520,216.

vided with curved doors 9, hinged thereto, and with two pipes 10, each provided with a cock, such as 11, screwed into the cover. Each of the doors is mounted on a rod 12, in cars 13, projecting from the body of the retort, and on the retort are mounted swinging bolts 14:, adapted to swing down behind projections 15 on the cover, thus firmly locking the covers in position. Any desired means, however, may be adopted for fastening the covers to the retort. The top and bottom covers are precisely similar.

14: represents a layer of asbestos, or similar refractory material, placed over the outer side of the retort, including the covers, and held in place by the wire netting 15, the ends of said netting opposite the cover portion being secured to the rods 12 by having the ends of the wires wrapped around it, as shown at 16.

The retort is thickened at the center, and from these thickened portions run shafts 17, one of which is provided with a pulley 18, to which power may be applied to rotate the retort, as hereinafter described. Ordinarily, the retort is suspended from atriangular frame 19, by means of depending supports therefrom, terminating in bearings 21, engaging the rods 17. W hen it is desired to move the retort, the lower half of each bearing is removed.

To hold the parts A, B and C firmly bound together, in case the bearings 20 are moved, I provide two stout upwardly-extending brackets 22, a. little below the center of the outside of the parts 3. These brackets are firmly fastened to the parts 3 by being bolted thereto, or made integral therewith, and have their upper parts bent outwardly for engagement wit-h the latches here inafter mentioned. With each of the brackets 22 a pivoted latch is adapted to engage, two of these latches being pivotally mounted on the part B, and two on the part G. Each latch 23 has its end thickened, as shown at 2-1, to pass down around the corresponding bracket 22, so that when the latches are in the position shown in Fig. 1, the parts A, B and C are prevented from longitudinal movement, except as a whole, being firmly locked together, with the ends of the parts 3 fitting into corresponding grooves in the parts 13 and C.

To the parts B and C are attached wheels 25, in the usual manner, which are adapted to run on tracks 26, so that the whole apparatus, consisting of the parts A, B and C may be moved as a whole from one part of the plant to another, the latches being in the position shown in Fig. 1, or whereby when the latches 23 are thrown up, the parts B and C may be separated from the retort A, whereupon the latter may be rotated by means of power applied to the pulley 18 for a purpose hereinafter described. The part B is the furnace portion, andis provided with a grate 26, pipe 27 for the admission of gaseous or liquid fuel, and door 28, provided with a latch 29. Of course, any desired form of fuel could be used in the part B.

The rear end of the part B is closed by a perforated plate 30, the perforations being located opposite the tubes 7 in the retort A. Around this perforated plate, the rear open end of the part B is thickened, as shown at 31, and is provided with a circular groove, into which groove the part 3 carried by the retort is adapted to fit.

The part C simply serves to carry the waste products of combustion after they have passed through the tubes 7 of the retort into the chimney. It consist-s of a flue, preferably cylindrical in form, having one end thickened, as shown at 32, said thickened end having a groove therein for the reception of the part 3 on one end of the retort A.

33 represents a chimney, and 34L the flue thereof. 85 represents a cylindrical opening, into which the open end of the part C is adapted to telescope. This arrangement is adopted so that the parts B and C may be moved along the track out of engagement with the retort A, leaving the latter free to rotate.

The operation is as follows :The apparatus being in the position shown in Fig. 1-, if it is desired to make gas, coke, and gas retort carbon, for example, the upper door of the retort is opened and a suitable charge of soft coal introduced into the interior of said retort into the space between the pipes 7. The upper door is then firmly closed, and connections made between the discharge pipes 10 at the top of the retort leading to the gasometer, or to any place where gas is to be used. A fire is then started in the furnace B, and the hot products of combustion pass through the tubes 7, distilling the coal in the retort A, the gases passing out through the discharge pipes 10. After this operation has been continued for a sufficient time to distil about half of the coal, the latches 23 are disengaged from the brackets 22, and the parts B and C moved along the track 26 out of contact with the retort A. All the cocks in the pipes 10 being closed, the upper pipes are disconnected from the pipes leading to the gasometer, and by means of power applied to the pulley 18, the retort is rotated 180. The parts B and C are then brought back into connection with the retort A, and the latches 23 moved down into the position shown in Fig. 1. The pipes at the top of the retort are then connected to the gas delivery pipes, and the cooks therein opened. The distillation process is then carried on to its close, and at the end the upper pipes are disconnected from the gas delivery pipes, and both the upper and lower doors are opened. By means of iron rods, the coke between the pipes 7 is forced down. out through the lower door, leaving the pipes 7, and in fact the whole interior of the retort, coated with an even layer of gas carbon.

The fact that the whole interior of the retort, including the pipes, is coated with an even layer of gas carbon, makes the retort highly useful in the production of sodium, for example, in which it is necessary that the substances under treatment should be subjected to the action of carbon under heat, and in which it is desirable that the retort should be frequently rotated. These retorts may be used either with or without carbon and are arranged in sets so that they can be moved from one part of the plant to another.

For some of the reactions hereinafter mentioned, it is necessary to have a certain amount of carbon in the retort and for other reactions there must be no carbon. To obtain this carbon, I charge the retort with soft coal and heat the same, up to the distillation point, by burning gas, coke, coal, or any desired kind of fuel in the furnace B. As the retort A becomes heated up, the gases from the fuel pass out of the upper pipes 10 in the usual manner, the cooks 11 being open, which gases are collected and either used to run another retort or stored for future consumption.

As described in the description of the apparatus, the retort is revolved 180 one or more times during the distillation process, so that the deposit of gas carbon within the retort on the tubes and walls thereof may be substantially uniform.

There is left in the retort coke and a deposit of gas carbon. The former may be removed by opening the top and bottom doors 9 of the retort and pushing out the coke from between the horizontal flues 7, leaving the deposit of gas carbon on the tubes and on the inside of the end plates and on the walls of the retort. This retort may be then used where it stands or conveyed away to another portion of the plant by latching the three parts A, B and C together and releasing the bearing around the rods or shafts 17 The South Carolina clays, which my process is primarily designed to treat (although it is by no means restricted to the treatment of these clays) consist of the following parts chemically combinedrrl O,, QSiO 2H1), XFe O that is to say; one molecule of alumina, two molecules of silica, two molecules of water, and l to 3 per cent. of ferrous or ferric oxids or both, approximately stated.

After determining the amount of alumina in the clay, I mix with one part of clay six times the amount of bi-sulfate of sodium, as compared with the alumina in the clay, basing the weights used upon the molecular weights of the alumina and the bi-sulfate of sodium, so that the latter salt may furnish enough sulfuric acid to give up 3 molecules of said acid to the alumina. In place of clay, I may, of course, use other ores of alumina, such as bauxite or corundum. The quantity of bi-sulfate of sodium used should, of course, be suflicient to furnish whatever iron is present with a sufficient amount of sulfuric acid, as well as the alumina, based upon the atomic weights of the oxids of iron and the bi-sulfate of sodium. This mixture is then heated in one of my retorts, producing a double sulfate of aluminum and sodium represented by the formula according to the following reaction It should be mentioned that the retort should only be charged so that it is about two-thirds full and before heating the retort it is separated from the furnace B and chimney connecting portion C and revolved, thus thoroughly mixing the materials to gether. Then the three parts A, B and C are reunited, as shown in Fig. 1, and the retort is heated by the furnace B. Sulfuric acid is set free from the bi-sulfate of sodium and attacks the clay, the mass becomes of a dark blue color and boils rapidly, and there is a rapid evolution of steam. Ferric alum is formed and also a new compound consisting of a double sulfate of aluminum and sodium, but having 3 molecules of sulfate of soda combined with 1 molecule of sulfate of aluminum. During the same reaction silica is also formed in an anhydrous condition, and when the reaction is ended, the mass assumes a dirty yellowish white color. As soon as the reaction is ended, the lower bearings of the retort A are removed and the whole apparatus being then free to move is rolled off the track to another portion of the plant. The upper and lower pipes in the retort are then opened and steam or hot water is passed in through the pipes at the top and is discharged through the pipes at the bottom, carrying out with it the contents of the retort. The double sulfates are dissolved out of the fused mass, leaving the silica in an insoluble form. The mass of material obtained by washing out the retorts is then filtered, separating the silica, which is washed again, if ne-essary, and is then in a fine white condition, admirably suited for making glass and other purposes for which silica is commonly used.

It will be noted that by my process the sulfate of alumina is united chemically with 3 molecules of sulfate of soda instead of with 1 molecule, as in ordinary alum, and by making use of this new double sulfate, I have devised an improved soda process.

To manufacture aluminate of soda, A1 0,, 3Na O, I place the double sulfate of soda and alumina already obtained in one of my carbon lined retorts, and heat it until the sulfate of alumina is decomposed, forming the oxid. Sulfurous acid is driven off, together with carbon monoxid and dioxid into a discharge pipe, which leads into a sulfuric acid chamber, where the usual treat ment for making sulfuric acid takes place. There is left in the retort alumina either mixed or chemically combined with 3 mole cules of sulfid of sodium, Al O tlNa S. I then add caustic lime in sufficient quantities to take up the sulfur, whereupon the following reaction takes place:

A1 0 ,3Na S+3CaO:Al 0 ,3Na O+3CaS.

The aluminate of soda thus produced is soluble while the sulfid of calcium is insoluble. The mass is allowed to cool and treated with water, whereupon the aluminate of soda dissolves and the sulfid of calcium can be separated from the solution by filtration or decantation.

YVhenever carbonates or caustic alkalies are heated at a red heat, the dificulty has been to keep the carbon which is lighter than the material treated, always in contact with the entire mass of the melted material.

In my retort, the gas carbon is fixed around the fines and outer portion of the retort and held there immovably, according to the react-ions already set forth. Accord ing to my method, a new double sulfate of alumina and soda, ferric alum, and free silica may be produced, as well as fiuorid of aluminum, sulfate of soda, metallic aluminum, artificial cryolite, metallic sodium, aluminate of soda, besides various others.

In a complete plant I design to use one series or battery of my retorts without distilling coal in them at all, and in another series, where it is desirable to use a carbon lined retort, coal is distilled, forming gas and a fresh lining of fresh carbon at every distillation, taking care in every distilling operation to tip the retort over, so that the bottom door is on the top and vice versa. The retort is preferably suspended from above by hanging supports, the bottom half bearings being lifted up to the shaft by bolts and screws, as shown in the drawing. The retort is detachably fixed to the furnace and chimney connecting portions by means of cylindrical projections fitting into circular grooves, and these with the latches support the retort A when it is released from its bearings, so that the whole structure, consisting of the three parts A, B and C .may be rolled away to another part of the plant.

I claim:

The herein described process of making sodium aluminate, which consists in heating clay in a closed retort with an excess of bisulfate of soda, making a double sulfate of soda and alumina,having three molecules of sulfate of soda to one of sulfate of alumina, heating said double sulfate in a retort lined with gas carbon, thereby driving off sulfur dioXid, heating the product with lime, and treating the fused mass with water, dissolving out aluminate of soda, substantially as described.

In testimony whereof, I afiix my signature, in presence of two witnesses.

PHILIP A. EMANUEL.

Witnesses T. AulVI'rHERsrooN, R. M. PARKER. 

